<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>该文件用于演示元素自身外边距相邻时的折叠</title>
	</head>
	<body>
		<div style="border: 1px solid red; width: 100px;">
			<div style="margin-top: 100px; margin-bottom: 50px;"></div>
		</div>
		
		
		
	</body>
</html>
